Zeolites have excellent adsorption characteristics, and for this reason, are used as adsorbents after ion exchange with various metal ions. From an industrial point of view, the zeolites used as adsorbents are used in the form of a zeolite molded article. The zeolite molded article is obtained by mixing a zeolite powder and a clay binder and then calcining the mixture.
Among various ion exchange zeolite molded articles, zeolite molded articles carrying silver by ion exchange have high adsorption characteristics. Accordingly, silver-containing zeolite molded articles are widely used as various adsorbents (for example, those disclosed in Patent Literatures 1 to 4).
Patent Literatures 1 and 2 describe methods of using silver ion-exchanged zeolite molded articles to remove moisture and sulfur compounds in gases. Here, the silver ion-exchanged zeolite molded article is prepared by subjecting a cylindrical zeolite molded article having a length of about 3 to 4 mm to silver ion exchange.
Patent Literature 3 describes a method of using a bead-like Ag-containing X type zeolite molded article having a diameter of 1.4 to 1.5 mm, to remove carbon monoxide, ethylene, propylene, and the like in air.
Patent Literature 4 discloses a zeolite molded article which obtained by granulating an X type zeolite powder that has been ion-exchanged with silver, to remove radioactive iodine contained in steam.
Patent Literature 5 discloses a method of treating an exhaust gas containing iodine or organic iodine using a silver-carrying zeolite molded article containing two types of zeolites, i.e., an X type zeolite and an A type zeolite, and containing no binder.